The present invention relates to a noise insulation structure of a cabin floor.
In an automotive vehicle as a vehicle, it is important to effectively reduce a noise transmitted to a cabin through a floor panel, in particular, to reduce a road noise by means of a floor carpet.
Japanese Patent Laid-Open Publication No. 2008-285026 discloses a structure in which plural layers of floor carpet are provided in order to insulate the noise sufficiently. Further, U.S. Pat. No. 6,685,250 discloses a noise insulation mechanism of the floor carpet which is explained in a mass-and-spring base manner.
It is general that the thickness of a sound-absorption material is set to be rather thick for improving the insulation property of the noise transmitted from the floor panel. In this case, however, there is a concern that the weight of the floor carpet may increase greatly and the height (vertical length) of the cabin may be deteriorated.